Fiberless flexible microactuator designed by finite-element method

The flexible microactuator (FMA) is a type of pneumatic rubber actuator with 3 degrees of freedom (DOF) developed by Suzumori (1991). It has been applied to various kinds of miniature robots. To achieve the required motion, conventional FMAs are made of a fiber-reinforced rubber, which makes the fabrication process complicated. The fabrication of FMAs from homogeneous rubber without fiber reinforcement is necessary if low-cost manufacture is to become a reality. In this paper, a new nonreinforced FMA design is developed using a nonlinear hyperelastic finite-element-method (FEM)-based sensitivity analysis. First, global analyses of FR/LA deformation are made for a wide range of design variables. This is important, to avoid falling into a local optimization. Next, precise optimization is carried out using a sensitivity analysis. Finally, a prototype of the fiberless FMA is fabricated and tested. This process demonstrates the feasibility of the new FMA design without fiber reinforcement, both theoretically and experimentally. This new design is suitable for mass fabrication of FMAs at low cost